LavMan -
What you have to realize to is that the lowest fare from LGA-SJU is 498.00 round trip. Compare that to LGA-BUF at 268.00, LGA-RDU at 300.00, LGA-PIT at 248.00 and the Shuttle weekend fare of 170.00. There is a lot of money to be made in the islands, and they are not destinations that you can drive to versus most of the short hops. Think about your last airport experience. The time it takes to check-in, check a bag, go through screening, get to the gate, board, deplane, get to baggage claim, get your bag, get your rental car, etc. If you had a choice of driving 300 miles or flying, which would you choose? Especially if it took you just as long either way, but driving was less hassle. That is why we need to pull away from the short haul flying and get into more long haul flying. BOS service started out as Sat only and will be going to daily service, if the market is there for LGA-SJU service you can look for it to go daily some day too.